Fair Value Measurements and Investments - Investment Income (Detail) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Sep. 30, 2023 |
Sep. 30, 2022 |
Sep. 30, 2021 |
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| Fair Value Disclosures [Abstract] | |||
| Interest and dividend income on cash and investments | $ 745 | $ 69 | $ (16) |
| Equity securities: | |||
| Unrealized gains (losses), net | (84) | (364) | 721 |
| Realized gains (losses), net | 2 | 68 | 26 |
| Investment income (expense) | $ 663 | $ (227) | $ 731 |
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- References No definition available.
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- References No definition available.
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- Definition Amount of operating dividend and interest income, including amortization and accretion of premiums and discounts, on securities. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount after accretion (amortization) of discount (premium), and investment expense, of interest income and dividend income on nonoperating securities. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of realized gain (loss) on investment. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of unrealized gain (loss) on investment. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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